Compression connector cap



Oct. 23, 1962 5. J. SPURGEON 3,060,258

COMPRESSION CONNECTOR CAP Filed Feb. 2, 1961 SMUEL J- SM/Q6600] 4* IN VEN TOR.

Unite States Filed Feb. 2, 1%1, Ser. No. 86,726 Claims. c1. 174-4 This invention relates to a compression connector cap and ground rod assembly for sinking an electrical ground wire into the earth to establish contact with electrically conductive earth strata.

Various prior art devices have been utilized from time to time for accomplishing the above stated purpose. Each involved means for fastening the ground wire to a ground rod which was then driven into the earth to a suitable depth. None of the prior devices succeeded in achieving a firm connection between the ground wire and ground rod with any degree of simplicity in structure. In addition the devices frequently required the use of complicated tools and also involved a significant amount of time in assembly.

An object of this invention is to provide a compression connector cap of simple construction which achieves a firm mechanical and electrical connection between the ground wire and ground rod without the use of special tools. Another object is to provide such a cap which can be easily and quickly assembled and is tamper-proof by unauthorized persons.

The present invention involves a cap member having a central cylindrical bore terminating in a flat sea-t portion within the cap. The cap has a plurality of smaller diameter internal cylindrical or semi-circular grooved portions along the bore aligned generally longitudinally therewith and disposed at spaced peripheral positions around the bore. The grooved portions open through the top of the cap and extend to the open end of the bore. The grooved portions gradually increase in depth from the seat to the open end of the bore and may or may not be of different diameters, being adapted to receive the terminal end of a respective ground wire through the cap. The central bore is adapted to receive a ground rod under force whereby the wire or wires, the rod and the cap are joined together. The forcing of the ground rod into the cylindrical bore compresses the wire between the cap and the rod to achieve a firm mechanical and electrical connection.

Other objects and features of the invention will appear in the specification and claims and in the drawings in which:

FIG. 1 is an elevation of the ground rod assembly;

FIG. 2 is a plan view taken along lines 2-2 of FIG. 1;

FIG. 3 is a section taken along lines 3-3 of FIG. 1;

FIG. 4 is a partially sectioned elevation taken along lines 4-4 of FIG. 3; and

FIG. 5 is a view similar to FIG. 4.

Referring now to the drawings FIG. 1 shows a ground rod assembly designated generally by the reference numeral which includes a ground rod 11, an electrical ground wire or conductor 12 and a cap 13. The cap 13 is made of metal, usually by casting, although it can be machined, forged or cold formed as desired and may be made of brass or any other suitable material. The configuration of the cap is generally triangular as shown although it may be fabricated in circular form or any other as desired.

Cap 13 has a central cylindrical bore 14 opening at the bottom 15 thereof and terminating preferably in a fiat seat portion 16 within the cap (see also FIGS. 2, 4). One or more smaller diameter internal cylindrical or semi-circular grooved portions 17, 18, 19 are disposed in said cap along bore 14 and are aligned generally longi- "ice tudinally therewith and disposed at spaced peripheral positions around the bore 14. The grooved portions open through the top 20 of the cap 13 with holes adapted to receive terminal portions 21 of an electrical ground wire 12 (only one shown). Each grooved portion 17, 18, 19 is of different diameter to receive or accommodate a ground Wire of corresponding size, and each grooved portion communicates with a respective hole 17a, 18a, and 19a having cross-sectional areas at least approximately equal to the cross-sectional areas of the corresponding Wires.

Each grooved portion has a gradually increasing depth, i.e. lateral dimension measured radially from said cylindrical bore 14, said depth gradually increasing from a position adjacent seat 16 to the outer end 22 of said bore 14. In other words, the grooved portions or smaller bores radially overlap the central bore 14 at the seat 16 and taper radially outwardly from the central bore to points of tangency therewith or even g eater distance therefrom at the outer end 22 of the central bore 14, i.e. the radial overlap of said smaller bores 17, 18, 119 with respect to said central bore 14 gradually decreasing in a direction away from said seat 16 toward the outer end 22 of central bore 14. That is, the respective cross-sectional areas of the three grooves 17, 18 and 19 increase over their lengths from minimums adjacent seat portion 16 to maximums adjacent bottom 15. The minimums are less than the cross-sectional areas of the corresponding ground wires. Ground rod 11 preferably has a tapered driving point 23 for insertion into the ground in the usual fashion and has cylindrical upper end 24 dimensioned to fit closely within bore 14 of cap 13 (see also FIGS. 3, 5).

In use terminal portion 21 of ground wire 12 is inserted through the top 20 of cap 13 in the grooved portion 1 9 which is suitably dimensioned to receive it. The ter- :minal portion 21 extend completely through the cap with an exposed end 25 extending through the bottom thereof and is bent radially outwardly to clear the cylindrical bore 14. Upper end 24 of ground rod 11 is forced into bore 14 :by any suitable means such as by hammering the cap down over the ground rod 11, whereby the -wire 12 is compressed between the cap 13 and the ground rod 11 as shown. The ground rod 11 actually bites into the wire 12 (see point 26) and thereby makes a firm mechanical and electrical interconnection therewith. The ground wire 12 is actually deformed by the pressure exerted when the cap 13 is driven on. The portion of the conductor within the opening 19a, however, remains substantially nondeforrned. In the case of a malleable type of ground rod, both wire and rod are deformed. Then the ground rod assembly can be suitably driven into the earth in the usual fashion, or the ground rod 11 can first be driven into the ground and then the ground wire 12 and cap 13 assembled thereon as previously described.

It is thus seen that the present invention provides a novel compression cap having simplicity of design and handling and showing marked advantages over devices used for similar purposes heretofore.

While one embodiment of the invention has been shown and described herein, it is to be understood that certain changes and additions can be made by those skilled in the art without departing from the scope and spirit of the invention. Such variations include utilizing a greater or lesser number of grooved portions and making them of the same or different diameters, as well as varying the cross-sectional shape of the grooves, i.e. making one or more rectangular, triangular, slotted, knurled, etc.

What is claimed is:

1. A fitting for joining an electrical ground conductor to a ground rod comprising a cap formed to provide a socket extending outwardly from a seat portion within the cap and adapted to receive one end of a ground rod, an axial groove adjacent said socket and extending 1ongitudinally thereof, said groove having a cross-sectional area which increases over its length from a minimum at one end thereof adjacent said seat portion to a maximum at the other end thereof, said minimum being less than the cross-sectional area of said ground conductor, and an opening through said cap member and in communication with said groove, said opening having a crosssectional area greater than said minimum and at least approximately equal to the cross-sectional area of said ground conductor.

2. A fitting for joining a plurality of electrical ground conductors to a ground rod comprising a cap formed to provide a socket extending outwardly from a seat portion Within the cap and adapted to receive one end of a ground rod, a plurality of axial grooves, one for each ground conductor, adjacent said socket and extending longitudinally thereof, each. of said grooves having a cross-sectional area which increases over its length from a minimum at one end thereof adjacent said seat portion to a maximum at the other end thereof, said minimum for each groove being less than the cross-sectional area of the ground conductor to be accommodated therein, and a plurality of openings through said cap member, one for each groove and each in communication with a respective groove, each of said openings having a crosssectional area greater than the minimum cross-sectional area of its respective groove and at least approximately equal to the cross-sectional area of the ground conductor to be accommodated in its respective groove.

3. A fitting for joining a plurality of electrical ground conductors to a ground rod as set forth in claim 2 wherein the cross-sectional areas of each of said grooves is difderent whereby conductors of different diameters may be accommodated simultaneously in said cap.

4. A fitting as set forth in claim 3 wherein said cap is of generally triangular configuration and wherein there are three axial grooves extending longitudinally of said socket.

5. In combination a ground conductor, a ground rod, and a fitting for joining the ground conductor to the ground rod, said fitting comprising a cap formed to provide a socket extending outwardly from a seat portion Within the cap, an axial groove adjacent said socket and extending longitudinally thereof, said groove having a cross-sectional area which increases over its length from minimum at one end thereof adjacent said seat portion to a maximum at the other end thereof, said minimum being less than the cross-sectional area of said ground conductor, an opening through said cap member and in communication with said groove, said opening having a cross-sectional area greater than said minimum and at least approximately equal to the cross-sectional area of said ground conductor, the terminal end of said ground conductor being disposed in said groove and said opening, and one end of said ground rod being positioned in said socket thereby compressing and biting into a portion of the conductor within said groove whereby said conductor, said ground rod and said cap are joined together as a unit.

References Cited in the file of this patent UNITED STATES PATENTS 937,130 Williams Oct. 19, 1909 1,001,054 Lawrence Aug. 22, 1911 1,679,677 Milne Aug. 7, 1928 2,547,176 Salmons Apr. 3, 1951 

